POWER ELECTRONICS

1. POWER ELECTRONICS CIRCUITS, DEVICES, AND APPLICATIONS Eng.Mohammed Alsumady

2. Relationship of Power Electronics

3. POWER ELECTRONICS TECHNOLOGY • As the technology for the power semiconductor devices and integrated circuit develops, the potential for applications of power electronics become wider. There are already many power semiconductor devices that are commercially available, however, the development in this direction is continuing. • The power semiconductor devices or power electronic converter fall generally into four categories : -AC to DC Converter (Controlled Rectifier) -DC to DC Converter (DC Chopper) -AC to AC Converter (AC voltage regulator) -DC to AC Converter (Inverter) •  The design of power electronics converter circuits requires design the power and control circuits. The voltage and current harmonics that are generated by the power converters can be reduced or minimized with a proper choice of the control strategy.

4. Power Electronics Application • Power Electronics defined as the application of solid-state (devices) electronics for the control and conversion of electric power. • Power electronics have already found an important place in modern technology and are now used in a great variety of high-power product, including heat controls, light controls, electric motor control, power supplies, vehicle propulsion system and high voltage direct current (HVDC) systems.

5. POWER ELECTRONIC SWITCHING DEVICES 1.Uncontrolled turn on and off (Power Diode) 2.Controlled turn on uncontrolled turn off (Thyristors) 3.Controlled turn on and off characteristic (Power Transistor, BJT, MOSFET, GTO, IGBT) 4.Continuous gate signal requirement (BJT, MOSFET, IGBT) 5.Pulse gate requirement (SCR(Silicon-Controlled Rectifier) , GTO) 6.Bidirectional current capability (TRIAC) 7.Undirectionalcurrent capability (SCR, GTO, BJT, MOSFET, IGBT)

6. Diagram Block of Converters

7. Diode Rectifiers. A diode rectifier circuit converts AC voltage into a fixed DC voltage. The input voltage to rectifier could be either single phase or three phase. • AC to DC Converters. An AC to DC converter circuit can convert AC voltage into a DC voltage. The DC output voltage can be controlled by varying the firing angle of the thyristors. The AC input voltage could be a single phase or three phase. • AC to AC Converters. This converters can convert from a fixed ac input voltage into variable AC output voltage. The output voltage is controlled by varying firing angle of TRIAC. These type converters are known as AC voltage regulators. • DC to DC Converters . These converters can converte a fixed DC input voltage into variable DC voltage or vice versa. The DC output voltage is controlled by varying of duty cycle.

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28. Examples of Some Applications

29. History of Power Electronics

30. Types of Power Devices

31. General Purposes Diodes

32. Thyristors

33. GTOs

34. Power Ratings of Devices

35. Ratings of Power Devices

36. Devices Symbols and Characteristics

37. Devices Symbols and Characteristics

38. Applications of Power Devices

39. Control Characteristics of Devices

40. Control Characteristics of Devices

41. Switching Characteristics

42. Ideal Characteristics Ideal Characteristics

43. Voltage and Current Waveforms

44. Diode Rectifiers

45. Ac-dc Converter • AC to DC Converters -Single phase, half wave AC to DC converter Input voltage Waveform of single-phase, half wave AC to DC converter α Output average voltage : rms value of Output voltage :

46. AC-DC Converter

48. 1. AC to DC Converters -Single phase, Full wave AC to DC converter The average output voltage can be found from :

49. AC to DC ConvertersSingle phase, Full wave AC to DC converter

50. 3 Phase Half-Wave Uncontrolled Rectifier with Inductive Load